A high voltage storage battery and a low voltage storage battery are mounted on the electric automobile or the plug-in hybrid vehicle. The high voltage storage battery is used as a power drive for driving the motor via an inverter device, and the low voltage storage battery is used for activating the accessory such as a light and a radio of the vehicle.
The vehicle of the above type has a DC-DC converter device for power conversion from the high voltage storage battery to the low voltage storage battery, or from the low voltage storage battery to the high voltage storage battery.
In the filter circuit connected to the power conversion device, the noise radiated from the power conversion circuit, which propagates through the space, and the electromagnetic noise generated by the eddy current flowing in the housing maybe superimposed on the filter circuit to cause the risk of deteriorating filter performance.
Patent Literature 1 discloses the known means for solving the aforementioned problem, only proposing the case having a metallic base section to which the ground potential is applied. The aforementioned related art still has the problem that the noise owing to the noise current superimposed on the base section is not taken into consideration.
It is demanded that the aforementioned DC-DC converter device should lessen the influence resulting from radiation of the electromagnetic noise generated in the device.